DIMM (dual in-line memory module) technology has random access memory (RAM) integrated circuits (ICs) mounted on a printed circuit board (PCB). Various types of DIMMs exist. DDR SDRAM (Double Data Rate Synchronous Dynamic Random Access Memory) DIMM technology has a parallel external interface. Fully buffered DIMM or FB-DIMM technology has a serial external interface.
FB-DIMM technology employs an Advanced Memory Buffer (AMB) having a serial connection to a memory controller, and a parallel connection to dynamic random access memory (DRAM). The AMB on each FB-DIMM translates the communication in serial point-to-point link protocol received from the memory host controller to DDR3 SDRAM parallel protocol transmitted to the DRAMs as read, write, refresh, etc. operations within the DIMM.
The PCB and FB-DIMM are coupled by connectors. The connectors are serial connection external interfaces. The standard pitch and/or center-to-center spacing of the connectors is approximately 0.5 in (12.7 mm) or more.